The relationship between spontaneous liquefaction and the characteristics of ejaculated human semen has been investigated. The liquefaction time of ejaculates was found to be significantly correlated with their extent of coagulation and some non‐enzymic components of seminal plasma. Human ejaculates were classified into 3 distinct groups depending on their liquefaction time, and the groups were characterized physico‐chemically. The liquefaction time also revealed a low but significant negative correlation with semen volume. It is concluded that an individual's ejaculatory characteristics can be evaluated simply by determining its liquefaction time. Copyright © 1985, Wiley Blackwell. All rights reserved